The Penicuik landslide, Midlothian, January 2007

This report describes the geological context, form and composition of a substantial rotational failure in artificial deposits on the southern bank of the River North Esk, approximately 0.5 km southwest of Penicuik town centre. Slippage of buried industrial waste resulted in collapse of a substantial volume of made ground, and associated tension cracking. Consequently the area was closed until the level of potential hazard could be assessed and remedial measures put in place. Slippage probably occurred as a result on prolonged and intensive rainfall in the weeks leading up to, as well as immediately prior to, the eventual failure. Elevated pore water pressures throughout the substrate, a raised water table, and slope-parallel stratification in the unconsolidated waste are likely to have combined to initiate the collapse.